It has been the practice in the prior art to stamp and form electrical contacts or terminals from a continuous strip of metal. The contacts at first were individually assembled to a printed circuit board and then soldered fixedly in place. The disadvantage of such a technique involved a requirement for hand labor to sort the contacts from one another, to assemble the contacts in desired alignment within the board, and to straighten the contacts in their final desired positions after soldering the contacts in place. Because hand labor is costly, there has been considerable effort directed toward reducing the amount of hand labor required for assembly of contacts to a printed circuit board. One of the first improvements to result from such effort resided in locating the terminals serially along a common carrier strip which was formed integral with the terminals during the stamping and forming process. This permitted the carrier strip to be fed into an insertion machine which individually severed a terminal from the strip and forcibly inserted it into a printed circuit board. The prior art further evolved into a technique whereby a plurality of electrical terminals along a common carrier strip were located within a comb-type tool which aligned the plurality of terminals for simultaneous insertion within corresponding locations in a circuit board. Using this technique, insertion of a larger number of terminals could be accomplished. When a plurality of terminals were simultaneously inserted, the common carrier strip served to align the terminals while the terminals were soldered fixedly in place within the printed circuit board. Subsequently, the carrier strip was removed from the terminals, leaving the terminals individually located within the printed circuit board.
Another version of the above techniques is described in U.S. Pat. No. 3,618,207 wherein a plurality of terminals, which extend transversely from a common carrier strip, have a body of insulating material molded transversely across the contacts, in the form of a continuous strip, before the carrier strip is sheared from the contacts. However, the disclosed insulative material is rigid and would prevent or hinder further steps forming the terminals into particular configurations. The molding operation is also relatively slow and costly.
According to another technique in the prior art, for example U.S. Pat. No. 3,582,865, a plurality of terminals were formed by etching out selected areas of metal plating on at least one side of a polyimide substrate. Such terminals generally required an additional substrate in order to be sufficiently rigid to make the desired electrical interconnection between circuit components, such as printed circuits and the like. Another similar multiple contact connector is described in U.S. Pat. No. 3,401,369. According to this patent, a plurality of contact members are formed on a sheet of dielectric material by conventional printed circuit forming techniques. A conductive ground plane is bonded to the opposite side of the dielectric sheet and the whole assembly is formed into a substantially U-shaped configuration to receive a plurality of spaced connectors, such as on the edge of a printed circuit board. This connector has the disadvantage of requiring multiple bonding steps which add to the cost and production time.
U.S. Pat. No. 3,239,798 describes a multiple contact connector in which a plurality of spaced-apart, elongated, parallel contact strips are formed from a sheet of electrically conductive material, preferably by a known etching technique. The strip is placed between two sheets of insulation material and bonded thereto along only certain predetermined lengths of the contact strips. The ends of the strips are not bonded. The ends of the strips are formed into alternate arcuately extending resilient contacts and the laminar center portion is formed into a channel. The alteration of the arcuate ends causes the non-bonded insulation material to be separated from the formed contact ends to allow electrical contact with suitable circuitry. The steps of forming the connector according to this patent are quite complex.